Strain insulator



Feb. 16 1926o l,572,937 w. H. KEMPTON STRAIN INSULATOR Filed August lO,1918 wmuEssEs; INVENTOR ,W Wz//ard/iiempafi Patented Feb. 16, 1926.

UNITED STATES PATENT OFFICE.

HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL--VANIA.

STRAIN INSULATOR.

Application' filed August 10, 1918. Serial No. 249,348.

T 0 all whom t may concern.'

Be it known that I, IVILLARD H, KEMrToN, a citizen of the United States,and a resident of IVilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in StrainInsulators, of which the Jfollowing is a specification.

My invention relates to strain insulators, and it has -for its primaryobject the construction of a highly eticient and cheap insulatorcomprising superimposed layers ol impregnated sheet material, andsuit-able connector elements.

One object of my invention is to provlide an insulator in which highinsulating qualities and great mechanical strength shall be combined.

Another objectot my invention is to construct a strain insulator whichshall be unaffected by wide temperature changes, moisture, oils, weakacids and alkalis.

A further object of my invention is to construct an insulator,comprising superimposed layers of impregnated sheet material,

by a method which will insure a product so uniform that both theelectrical and mechanical insulating qualities may be accuratelydetermined.Y

A still further ob-ject of my invention is to provide a molded straininsulator in which the connector elements may be molded in place at thesame time that the insulator is pressed and cured in a mold.

Vith these and other objects in view, my invention will be more fullydescribed; illustrated in the drawings, in which corresponding numeralsindicate like parts, and then more particularly pointed out in theappended claims.

In the drawings Fig. lis a side elevation, partly in section, of astrain insulator con structed in accordance with my invention; Fig. 2 isan elevational view of a connector element which may be employed inconstructing my improved insulator, and Fig. 3 is a longitudinalsectional view of a modified form of insulator embodying my invention.

In practicing'my invention, I may construct a strain insulator byemploying an impregnated sheet material which may be wound aboutmetallic connector elements disposed at the end of the material so thatthe material engages portions of the metallic members while otherportions of the members project beyond it. The material may thus bewound about the connectors to form a rod and the rod may be disposed ina mold and subjected to heat and pressure to compact it and harden thebinder.

The metallic members may consist of wire bentl and twisted in suchmanner as to form a loop having extending and distorted end portionswhich will insure better binding action between the impregnated materialand the wire, Each connect-or element may also be formed of a metallicribbon which may he bent to form a loop, the ends of which may betwisted about each other or may remain in parallel relation to eachother and be twisted separately. The ribbonformed connectors may beinserted in the rod in the' same manner as the wire.

Referring to the drawings, in Fig. 1 is shown an insulator 3 constructedot' sheet material, impregnated with a binder, such as a phenoliccondensation product and having metallic connector element-s 4 molded inits ends. Each connector element 4 may be formed of a wire which may bebent and may have its ends twisted about each other in such manner thata loop 5 and a distorted shank are provide. The connector elements 4,thus formed, may be positioned in the rod 3 by winding the sheetmaterial forming the rod 3 about them so that, when the rod 3 ispositioned in a mold and subjected to heat and pressure, the compactedmaterial, together with the hardened binder, will secure the connectorelements 4 firmly in place.

An insulator 6, such as is shown in Fig. 3, may be constructed in asimilar manner, the principal ditference being in the connector elements7 which, in this instance, are bent to form a loop 8 havingits ends 9extending in parallel relation to each other,

and, if desired, separately twisted to insure greater binding effectwhen positioned in the impregnated sheet material forming the rod 6 orits ends 9 may be twisted about each other, to form a shank, as desired.

An insulator constructed in accordance with my invention combines highinsulating qualities with great mechanical strength. rThe laminatedstructure of the insulators insures great resistance against stresses inany direction. The insulating qualities ot my improved insulator havebeen tested with voltages suiicient to cause a spark to bridge the gapbetween conductor elements which bent they held in spaced relation andin no instance did the high voltages in any Way damage the rod. Ast-hese'insulators are in no Way affected by comparatively Widetemperature changes or moisture, they may be employed under anyatmospherical conditions that may be experienced.

Although I have shown particular forms of insulators Which may beconstructed in accordance With my invention, it is obvious that otherminor changes may be made in constructing an insulator Without departingfrom the spirit of my invention and I desire, therefore, that nolimitations shall be imposed except such as are indicated in theappended claims.

claim as my invention:

1. A strain insulator comprising a rod formed of superimposed layers ofsheet material impregnated With. a hardened binder and metallic membersbent tolform loops and having their ends distorted and molded into theends ot' the rod.

2. A strain insulator comprising a rod formed of superimposed layers ot.sheet material impregnated with a hardened phenolic condensationproduct and metallic members to form loops and having their endsdistorted and molded into the ends of the ro 3. A strain insulatorcomprising a' rod formed of superimposed layers of sheet materialimpregnated with a hardened binder and Wires bent to form loops andseverally having-their ends twisted about each other and molded into theends of the rod.

Y 4. A strain insulator formed of superimposed layers of sheet material.impregnated With a hardened phenolie condensation product and wires'bentto comprising a rodi form loops and severally having their ends twistedabout each other and molded into the ends of the rod.

5. A strain insulator comprising a rod formed of superimposed layers ofsheet material impregnated with a hardened binder and Wires bent to formloops and having their ends twisted and molded into the ends of the rod.

6. An insulator comprising a hard molded insulating body includingelements therein having portions extending substantially parallel to itsload axis and portions, constituting longitudinal continuations oi' saidfirst portions, that are laterally waved or bent, and a terminal memberembodying' an intermediate loop portion and laterally-extending portionsdisposed between said Waves or bends for interlocking' the insulatingbody and terminal member againt the load forces.

7. A strain insulator comprising an elongated hard molded insulatingbody including elements therein having intermediate portions extendingsubstantially parallel to its longitudinal load axis and portions,constituting longitudinal continuations ot said first portions, that arelaterally waved or bent adjacent to the ends of said body, and terminalmembers each embodying an intermediate loop portion and ends havinglatemily-extending portions disposed between said Waves at one end ofthe insulating body for interlocking the latter andthe terminal membersagainst the load forces.

In testimony whereof, I have hereunto= subscribed 1918.

my name this 7th day of August IVILLARD H. KEMPTON.

ends having

